Well after the service had begun, De Blasio, wearing a dark suit and green tie, was all smiles as he was ushered to his seat in the front row. He shook hands with some along the way as he breezed by the packed pews, CBS2’s Weijia Jiang reported.

The mayor was delayed after a traditional breakfast for Irish leaders at Gracie Mansion ran long.

“We had a great delegation here from the Irish government, but they had to go ahead to the Mass,” de Blasio said.

The mayor said he and his team will rectify the problem in the future, WCBS 880’s Peter Haskell reported.

“For a variety of reasons, the program ran a little long. I left as soon as it was over,” de Blasio said. “I think the moral of the story is I think we’re going to start the breakfast even earlier next year.”

De Blasio Arrives Late For St. Patrick's Day Mass At Cathedral

Some New Yorkers were not thrilled with the mayor’s tardiness.

“It’s disrespectful to the city of New York. He’s there for the people,” said Jonathan Baston of Harlem. “He can be on time. If I can be on time for my 9 to 5, as the mayor, he should be on time.”

But this was not the first such incident. In fact, de Blasio’s latest bout with tardiness came less than 24 hours after he vowed to be on time, CBS2’s Marcia Kramer reported.

“There’s always a lot going on, but as I have said one of my New Year’s resolutions (was) to work on punctuality. I will continue to do so,” the mayor said.

His tardiness has been such an ongoing issue that on Monday the news website DNAInfo published a “Mayoral Excuse Machine,” in which users can borrow past de Blasio excuses to explain their own lateness.

Mayor Bill de Blasio Arrives Late For St. Patrick's Day MassMayor Bill de Blasio walks in front of the first pew after arriving 15 minutes late to mass at St. Patrick's Cathedral on March 17, 2015. (credit: CBS2)

Mayor Bill de Blasio Arrives Late For St. Patrick's Day MassMayor Bill de Blasio shakes hand in front of the first pew after arriving 15 minutes late to mass at St. Patrick's Cathedral on March 17, 2015. (credit: CBS2)

Mayor Bill de Blasio Arrives Late For St. Patrick's Day MassMayor Bill de Blasio takes his seat in the first pew after arriving 15 minutes late to mass at St. Patrick's Cathedral on March 17, 2015. (credit: CBS2)

Mayor Bill de Blasio Arrives Late For St. Patrick's Day MassMayor Bill de Blasio sits in the first pew after arriving 15 minutes late to mass at St. Patrick's Cathedral on March 17, 2015. (credit: CBS2)

Mayor Bill de Blasio Arrives Late For St. Patrick's Day MassMayor Bill de Blasio, seen standing in shadow in the front left, arrives about 15 minutes late to St. Patrick's Day mass on March 17, 2015. (credit: CBS2)

Parade organizers waited 10 minutes before starting without de Blasio, and the banner reading “Mayor of New York Bill de Blasio” was reportedly carried for 14 blocks — half of the parade route — without the mayor anywhere in sight.

He said meetings at Gracie Mansion “took a while,” and he’d taken a police boat to arrive as soon as possible.

He said fog delayed his police boat that day and that he’d had a “rough night” of sleep.

De Blasio also has routinely kept reporters waiting at scheduled news conferences.

De Blasio did not participate in Tuesday’s St. Patrick’s parade on Fifth Avenue over concerns that not enough gay groups were being allowed to take part. Paradegoers said they did not appreciate his late arrival at the Mass, Kramer reported.

“He should be on time. It’s a special day for the Irish. (It would) be more respectful if he were on time, but if he’s a notoriously late person, what do you expect?” Donna Glemud said.

“He should have made it,” another person added.

Political analyst Hank Sheinkopf told Kramer it was not good to be late to Mass.

“Being late to Mass in one of the city’s holiest places on St. Patrick’s Day is not the best idea,” Sheinkopf said.

And etiquette experts, who always have an answer, said voters could start questioning the mayor’s other skills.

“They begin to think. ‘Is this an organized person? Is this someone we can rely upon? And does this person really care about us?’” said Lena Koropey, founder of Gramercy Protocol.